Low energy fast events from radon progenies at the surface of a CsI(T?) scintillator

摘要

In searches for rare phenomena such as elastic scattering of dark matter particles or neutrinoless double beta decay, alpha decays of ~(222)Rn progenies attached to the surfaces of the detection material have been identified as a serious source of background. In measurements with CsI (T?) scintillator crystals, we demonstrate that alpha decays of surface contaminants produce fast signals with a characteristic mean-time distribution that is distinct from those of neutron- and gamma-induced events.